Filters - MERV 13, Myths & More

In this episode of the HVAC School Podcast, Bryan sits down with Kelsey Hei and Andy Fox from 3M Filtrete to pull back the curtain on what really goes into a quality air filter. Most homeowners — and even some contractors — think of air filters as simple screens that catch dust, but as this episode makes clear, modern filter technology is anything but simple. From proprietary nonwoven fiber structures to electrostatic charging that turns fibers into "magnets" for microscopic particles, the science behind a great air filter is both fascinating and critically important for equipment health and the air we breathe every day.

The conversation digs deep into why MERV 13 has become the gold standard recommendation from organizations like the EPA and CDC — especially in the wake of COVID-19 and worsening wildfire seasons across the country. While higher MERV ratings deliver better particle capture, they can also mean higher pressure drop, which strains HVAC equipment. This is where Filtrete's MPR 1900 filter stands out: it achieves MERV 13 performance while maintaining a pressure drop comparable to most MERV 8 filters — roughly half that of leading competitors. That balance between filtration efficiency and airflow resistance is something 3M has spent over 35 years engineering.

One of the most compelling segments focuses on real-world testing. Rather than relying solely on lab data, 3M runs extensive in-home studies — placing filters in dozens of homes during Minnesota winters, then retrieving and analyzing them to measure real-life efficiency and pressure drop. This commitment to real-world validation ensures Filtrete's claims hold up in the messy, variable conditions of actual homes, not just controlled lab environments. Bryan and the guests also discuss how overloaded or collapsed filters can cause serious equipment issues, including frozen coils and system shutdowns in extreme cases — underscoring why filter quality and regular replacement matter enormously.

The episode wraps with practical advice for contractors and homeowners alike: if you're installing a new system, push for a four- or five-inch filter slot to maximize surface area, lower ongoing pressure drop, and extend filter life. For existing one-inch slots, the MPR 1900 is the top pick. The Filtrete Smart App is also highlighted as a handy tool for setting filter change reminders and monitoring local air quality — making it easier than ever for consumers to stay on top of their indoor air health.

Topics Covered

· 3M Filtrete's history — 35+ years of indoor air quality innovation, owning the full manufacturing value chain from raw fiber to finished filter